As a luminescent material that emits green light by the excitation of blue light (green-emitting luminescent material), an Eu-activated alkaline earth orthosilicate luminescent material has been recently suggested. Such a green-emitting luminescent material, a luminescent material that emits red light by the excitation of blue light (red-emitting luminescent material), and a blue LED are combined to constitute a white light-emitting device. The blue LED is driven to generate heat, and thereby to increase the temperature of the luminescent material. When the temperature is increased, the emission intensity of the luminescent material is generally reduced.
There is a high demand for the luminous efficiency and temperature characteristics of the luminescent material.